Modification of silica with a covalently attached antigen for use in immunosorbent assays

This paper describes the preparation and characterization of a silica surface with a covalently coupled antigen, and gives an example of the use of the modified silica in immunosorbent assays. Silica beads and slides were cleaned with chromic acid and modified with 3-aminopropyltriethoxysilane. The carboxyl groups of a cyclic hexapeptide antigen, ferrichrome A, were coupled to the amine-modified silica using 1-ethyl,3,3-dimethylaminopropyl cabodiimide to promote formation of a peptide bond. Modified slides and beads were characterized with a combination of X-ray photoelectron spectroscopy and particle electrophoresis measurements, with the amount of ferrichrome A adsorbed of coupled to the beads being determined by solution depletion measurements.